Tube fitting



Dec. 31, 1929. w. M. CRO-ss 1,742,175

TUBE FITTING Filed May 12, 1924 Patented Dec. 31, 1929.

UNITED Is'ra'rasy P aTNr OFFICE WALTER IMI. GROSS, OF`KAN'SAS CITY, MISSOURI TUBE `FITTING Application led May 12,

` they are set in a tube sheet may be used and removed without destroying or mutilating the connection to the adjoining tubes; to

provide a construction which permits the use of any desired type of metal and particularly those metals which cannot successfully be expanded into tube end fittings; to provide` a construction whereby tubes may be easily and readily removed and replaced and, in general, to provide a construction hereinafter more fully described.

In the drawings: l i

Fig. 1 is a sectional side view of the end fittings of two tubes showing the removable construction. l

Fig. 2 is a view taken along the line 2-2 in Fig. l, looking in the direction of thearrows. 1

In describing the figures in connection with the accompanying drawings, let it be understood that in order to disclose the invention in sufficient size only a portion ofthe ends of two of the tubes are shown with the tube end fittings which form the subject of the present invention. Further, the cleaning plugs, hereinafter briefly mentioned and explained, form a part of a separate invention covered in application No. 359,642, filed February 18', 1920. The tube fittings hereinafter described are connected in the ends of tubes 5 positioned in a furnace or heating means in order that the tubes may be more readily removed either to be cleaned or in case they are worn out or defective. Replacement of tubes in either a steam boiler or heating tube construction which is used for heating liquids 1924. serial No. 712,846.

such as oil or the like, is usually a very tedious' and often a difficult task, as normallyl it is the practice to expand the tube ends into headers, fittings or tube sheets and the removal of the single tube necessitates the removal also ofthe adjoining tubes connected in the same fitting.

In order to obviate this difficulty, the pres-v ent construction provides for they replace- `ment of the individual tubes by removing holding members or externally threaded bushings which serve, when screwed in place, to 'draw the tubesy rigidly against the end tube fittings.

Referring to the drawings, at l are shown heating tubes through which is circulated the medium or gas to betreated. On the ex-v terior of these 'tubes are shown a plurality of fins 2 which serve to providea vmore efficient heat transfer more specifically claimed in a separate pending application. At 3 are showntube supports which hold the tubes in place in the furnace. ll is an end fitting which, in this particular construction, en-

r closes the ends of two tubes although it is understood that as many tubes may be ineluded in one of these end fittings as isideemed desirable. In the end face of the fitting are \cleaning apertures closed by means of obturator plugs 5 held in place on ground seats by follower members 6 and holding screws 7. These plugs are positioned in line with the ends of the tubes in order that they may be removed and the tubes cleaned whenever necessary. The particular construction and novelty of these plugs is claimed in the pending application hereinbefore referred to.

The tubes are preferably externally tapered near their ends, as shown at 8, to form a close fit with the internally tapered faces of the fitting 4, VAt these tapered points of f contact, this type of joint may be replaced, if desired, by vertical contacting surfaces with gaskets placed therebetween to assure pressure-tight connections. i y p The tubes are internally threaded to permit engagement of the externally threaded buslr ings 9. These bushings, instead of having cylindrical apertures therethrough, are internally hexagonal in shape in order to be set Jends of the tubes.

and removed by means of a socket wrench. When screwed in place in the tubes, the shoulders 9 of the bushings contact the fittings and draw up the tapered surfaces of the tubes and tube end fittings to form pressuretight, connections. In removing or replacing any of the tubes, the cleaning plugs at the ends ofthe fittings are taken out and a socket wrench used to remove the bushings in the The tubes can then be readily taken out and the fittings disconnected and new tubes put in in a very short period of time and without mutilating or destroying any of the adjoining-tubes in the same fittings. It is obvious that the tube end fittings are identical at both ends of the furnace.

As mentioned, these pressure bushings facilitate the replacement of tubes, also assure pressure-tight connections between the tubes and tube'fittings and permit the use of tubes of different metals which, due to the character of the metal, cannot be satisfactorily expanded into tube end fittings. A further advantage is the fact that tubes, such as those shown in the drawings which are of larfer diameter than the openings in the tube fittings into which they are connected, may be replaced without drawing the tubes through the apertures in the fitting as is closure member enclosing a plurality of tube ends,externally threaded bushings engaging the interior of the tubes and having enlarged heads adapted to abut the closure member, a tapered seat onthe tube end adapted to be drawn into pressure tight friction fit with a contiguous tapered seat on the closure by said bushin g WALTER M. CROSS.

usually the practice. This type of construction, due to these Iadvantages, lends itself admirably to boiler construction where a tube sheet is utilized. In such a type of construction at the present time only a plain tube can be used in a furnace without mutilating good tubes when removing a defective one `within the same fitting.

I claim as my invention:

1. In end fittings for tubes the combination with a closure member enclosing the tube ends of apertures in the closure member into which the tubes are fitted directly, removable cleaning plugs opposite the tube ends, and removable means having threaded engagement with the tubes and adapted to draw the tubes into the apertures in the closure to form pressure tight connections between the closure members and the tube ends.

2. In end fittings for tubes the combination with a tube support and a closure member, enclosing tube ends, of apertures in the closure member into which the tubes tit, removable externally threaded bushings having enlarged heads, adapted to engage nter nal threads in the tubes and the closure member, and to produce a pressure-tight joint between the tube ends and the closure members independently of the tube support.

3. In end fittings for tubes the combination with a tube support and a closure-member enclosing the tube ends, 4of apertures in the closure member into which the tubes fit, removable cleaning plugs opposite the tube ends, fitted in apertures in the end fittings, 

